[FFmpeg-devel] [PATCH] avfilter: add asubcut filter
Paul B Mahol
onemda at gmail.com
Mon Nov 30 14:49:06 EET 2020
Signed-off-by: Paul B Mahol <onemda at gmail.com>
---
doc/filters.texi | 25 +++++++++++
libavfilter/Makefile | 1 +
libavfilter/af_asupercut.c | 89 ++++++++++++++++++++++++++++++--------
libavfilter/allfilters.c | 1 +
4 files changed, 97 insertions(+), 19 deletions(-)
diff --git a/doc/filters.texi b/doc/filters.texi
index 06ed28f3f9..348cdae4e9 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -2636,6 +2636,28 @@ Default value is 20.
This filter supports the all above options as @ref{commands}.
+ at section asubcut
+Cut subwoofer frequencies.
+
+The filter accepts the following options:
+
+ at table @option
+ at item cutoff
+Set cutoff frequency in Hertz. Allowed range is 2 to 200.
+Default value is 20.
+
+ at item order
+Set filter order. Available values are from 3 to 20.
+Default value is 10.
+
+ at item level
+Set input gain level. Allowed range is from 0 to 1. Default value is 1.
+ at end table
+
+ at subsection Commands
+
+This filter supports the all above options as @ref{commands}.
+
@section asupercut
Cut super frequencies.
@@ -2649,6 +2671,9 @@ Default value is 20000.
@item order
Set filter order. Available values are from 3 to 20.
Default value is 10.
+
+ at item level
+Set input gain level. Allowed range is from 0 to 1. Default value is 1.
@end table
@subsection Commands
diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index cff9402989..03998dc064 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -90,6 +90,7 @@ OBJS-$(CONFIG_ASR_FILTER) += af_asr.o
OBJS-$(CONFIG_ASTATS_FILTER) += af_astats.o
OBJS-$(CONFIG_ASTREAMSELECT_FILTER) += f_streamselect.o framesync.o
OBJS-$(CONFIG_ASUBBOOST_FILTER) += af_asubboost.o
+OBJS-$(CONFIG_ASUBCUT_FILTER) += af_asupercut.o
OBJS-$(CONFIG_ASUPERCUT_FILTER) += af_asupercut.o
OBJS-$(CONFIG_ATEMPO_FILTER) += af_atempo.o
OBJS-$(CONFIG_ATRIM_FILTER) += trim.o
diff --git a/libavfilter/af_asupercut.c b/libavfilter/af_asupercut.c
index ef241405d8..6d0a2b79a9 100644
--- a/libavfilter/af_asupercut.c
+++ b/libavfilter/af_asupercut.c
@@ -32,6 +32,7 @@ typedef struct ASuperCutContext {
const AVClass *class;
double cutoff;
+ double level;
int order;
int filter_count;
@@ -95,27 +96,52 @@ static int get_coeffs(AVFilterContext *ctx)
s->filter_count = s->order / 2 + (s->order & 1);
calc_q_factors(s->order, q);
- if (s->order & 1) {
- BiquadCoeffs *coeffs = &s->coeffs[0];
- double omega = 2. * tan(M_PI * w0);
+ if (!strcmp(ctx->filter->name, "asubcut")) {
+ if (s->order & 1) {
+ BiquadCoeffs *coeffs = &s->coeffs[0];
+ double omega = 2. * tan(M_PI * w0);
- coeffs->b0 = omega / (2. + omega);
- coeffs->b1 = coeffs->b0;
- coeffs->b2 = 0.;
- coeffs->a1 = -(omega - 2.) / (2. + omega);
- coeffs->a2 = 0.;
- }
+ coeffs->b0 = 2. / (2. + omega);
+ coeffs->b1 = -coeffs->b0;
+ coeffs->b2 = 0.;
+ coeffs->a1 = -(omega - 2.) / (2. + omega);
+ coeffs->a2 = 0.;
+ }
+
+ for (int b = (s->order & 1); b < s->filter_count; b++) {
+ BiquadCoeffs *coeffs = &s->coeffs[b];
+ const int idx = b - (s->order & 1);
+ double norm = 1.0 / (1.0 + K / q[idx] + K * K);
- for (int b = (s->order & 1); b < s->filter_count; b++) {
- BiquadCoeffs *coeffs = &s->coeffs[b];
- const int idx = b - (s->order & 1);
- double norm = 1.0 / (1.0 + K / q[idx] + K * K);
+ coeffs->b0 = norm;
+ coeffs->b1 = -2.0 * coeffs->b0;
+ coeffs->b2 = coeffs->b0;
+ coeffs->a1 = -2.0 * (K * K - 1.0) * norm;
+ coeffs->a2 = -(1.0 - K / q[idx] + K * K) * norm;
+ }
+ } else {
+ if (s->order & 1) {
+ BiquadCoeffs *coeffs = &s->coeffs[0];
+ double omega = 2. * tan(M_PI * w0);
+
+ coeffs->b0 = omega / (2. + omega);
+ coeffs->b1 = coeffs->b0;
+ coeffs->b2 = 0.;
+ coeffs->a1 = -(omega - 2.) / (2. + omega);
+ coeffs->a2 = 0.;
+ }
- coeffs->b0 = K * K * norm;
- coeffs->b1 = 2.0 * coeffs->b0;
- coeffs->b2 = coeffs->b0;
- coeffs->a1 = -2.0 * (K * K - 1.0) * norm;
- coeffs->a2 = -(1.0 - K / q[idx] + K * K) * norm;
+ for (int b = (s->order & 1); b < s->filter_count; b++) {
+ BiquadCoeffs *coeffs = &s->coeffs[b];
+ const int idx = b - (s->order & 1);
+ double norm = 1.0 / (1.0 + K / q[idx] + K * K);
+
+ coeffs->b0 = K * K * norm;
+ coeffs->b1 = 2.0 * coeffs->b0;
+ coeffs->b2 = coeffs->b0;
+ coeffs->a1 = -2.0 * (K * K - 1.0) * norm;
+ coeffs->a2 = -(1.0 - K / q[idx] + K * K) * norm;
+ }
}
return 0;
@@ -135,6 +161,7 @@ static int filter_channels_## name(AVFilterContext *ctx, void *arg, \
AVFrame *in = td->in; \
const int start = (in->channels * jobnr) / nb_jobs; \
const int end = (in->channels * (jobnr+1)) / nb_jobs; \
+ const double level = s->level; \
\
for (int ch = start; ch < end; ch++) { \
const type *src = (const type *)in->extended_data[ch]; \
@@ -150,7 +177,7 @@ static int filter_channels_## name(AVFilterContext *ctx, void *arg, \
type *w = ((type *)s->w->extended_data[ch]) + b * 2; \
\
for (int n = 0; n < in->nb_samples; n++) { \
- type sin = b ? dst[n] : src[n]; \
+ type sin = b ? dst[n] : src[n] * level; \
type sout = sin * b0 + w[0]; \
\
w[0] = b1 * sin + w[1] + a1 * sout; \
@@ -240,6 +267,7 @@ static av_cold void uninit(AVFilterContext *ctx)
static const AVOption asupercut_options[] = {
{ "cutoff", "set cutoff frequency", OFFSET(cutoff), AV_OPT_TYPE_DOUBLE, {.dbl=20000}, 20000, 192000, FLAGS },
{ "order", "set filter order", OFFSET(order), AV_OPT_TYPE_INT, {.i64=10}, 3, 20, FLAGS },
+ { "level", "set input level", OFFSET(level), AV_OPT_TYPE_DOUBLE, {.dbl=1.}, 0., 1., FLAGS },
{ NULL }
};
@@ -276,3 +304,26 @@ AVFilter ff_af_asupercut = {
.flags = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC |
AVFILTER_FLAG_SLICE_THREADS,
};
+
+static const AVOption asubcut_options[] = {
+ { "cutoff", "set cutoff frequency", OFFSET(cutoff), AV_OPT_TYPE_DOUBLE, {.dbl=20}, 2, 200, FLAGS },
+ { "order", "set filter order", OFFSET(order), AV_OPT_TYPE_INT, {.i64=10}, 3, 20, FLAGS },
+ { "level", "set input level", OFFSET(level), AV_OPT_TYPE_DOUBLE, {.dbl=1.}, 0., 1., FLAGS },
+ { NULL }
+};
+
+AVFILTER_DEFINE_CLASS(asubcut);
+
+AVFilter ff_af_asubcut = {
+ .name = "asubcut",
+ .description = NULL_IF_CONFIG_SMALL("Cut subwoofer frequencies."),
+ .query_formats = query_formats,
+ .priv_size = sizeof(ASuperCutContext),
+ .priv_class = &asubcut_class,
+ .uninit = uninit,
+ .inputs = inputs,
+ .outputs = outputs,
+ .process_command = process_command,
+ .flags = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC |
+ AVFILTER_FLAG_SLICE_THREADS,
+};
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index 83f434bc27..d0fb7bfe9d 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -83,6 +83,7 @@ extern AVFilter ff_af_asr;
extern AVFilter ff_af_astats;
extern AVFilter ff_af_astreamselect;
extern AVFilter ff_af_asubboost;
+extern AVFilter ff_af_asubcut;
extern AVFilter ff_af_asupercut;
extern AVFilter ff_af_atempo;
extern AVFilter ff_af_atrim;
--
2.17.1
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